Zuiko (Japanese: ズイコー or 瑞光) is a brand of optical lenses[1] made by Olympus Corporation that was used up to and into the Four Thirds system era. The name Zuiko (瑞光) means 'Holy Light', using a character from the Mizuho Optic Research Laboratory (瑞穂光学研究所), where the lens was developed, and a character from Takachiho Corporation (高千穂製作所), which would eventually become the Olympus Corporation.[2][3]
With the introduction of the Micro Four Thirds system in 2008, new lenses for that system started to be branded as M.Zuiko Digital.